Which is not a test for who must file a tax return?

Question $9$ options:

$1)$

Dependent with unearned income greater than $$1,300$

$2)$

Gross income is greater than $($standard deduction plus personal exemption plus additional deduction for age$)$

$3)$

Net self$-$employment income is greater than $$450$

$4)$

Taxpayer has positive taxable income